It is known that three-dimensional display of a plurality of combined images may provide a parallax-based stereo vision. Such stereo vision may be realized by imaging the same subject from different positions using a plurality of cameras to obtain a plurality of images, and three-dimensionally displaying the plurality of images using a parallax between each of the plurality of images.
More specifically, for a method that realizes stereo vision by naked eye parallel viewing, the three-dimensional display may be implemented by arranging a plurality of images side by side. Further, a plurality of images may be combined and displayed three-dimensionally by superimposing a plurality of images having different colors, e.g., red and blue, or by superimposing a plurality of images having different polarization directions. In this case, the stereo vision may be realized by fusion viewing the three-dimensionally displayed image through the auto focus function of the eyes using image separation glasses, such as red-blue glasses, polarized glasses, or the like (anaglyph method, polarizing filter system).
Further, it is also possible to realize the stereo vision by displaying a plurality of images on a three-dimensional display monitor capable of providing stereo vision without using the polarizing glasses or the like as in the parallax barrier system and lenticular system. In this case, the three-dimensional display is implemented by vertically cutting a plurality of images in strips and alternately disposing the strips. Still further, a method that performs a three-dimensional display by changing the light beam direction in left and right images through the use of an image separation glasses or application of an optical element on the liquid crystal and alternately displaying the left and right images is also proposed (scan backlight method).
In addition, a compound eye camera which has a plurality of imaging units and performs imaging for the three-dimensional display is proposed. Such a compound eye camera includes a three-dimensional display monitor, and is capable of generating a three-dimensional image for a three-dimensional display from images obtained by the plurality of imaging units and three-dimensionally displaying the generated three-dimensional image on the three-dimensional display monitor.
Such a compound eye camera needs to display a camera setting menu, imaging conditions, such as F number and shutter speed at the time of imaging, characters representing the number of images taken and date and time of imaging, icons indicating anti-camera shaking, ON/OFF of flash light, portrait mode, and the like, and objects such as pictogram. The photographer may confirm the date and time of imaging, the number of images taken, the imaging conditions at the time of imaging, and the like by confirming such objects.
Here, when displaying such an object in three-dimensional display, if the object is displayed three-dimensionally by arranging them in each of a plurality of images so as to have a parallax, not only the image but also the object is stereoscopically viewable. In this respect, a method in which depth information is give in advance to objects to be displayed, then depth information of a specified object is compared to that of the other objects, and the depth information of the specified object is changed such that the specified object is displayed in front of the other objects is proposed as described, for example, in Japanese Unexamined Patent Publication No. 2005-065162. Further, a method in which, when three-dimensionally displaying an object specified among a plurality of two-dimensionally displayed objects, positions and sizes of the specified object and an object likely to overlap with the specified object, and the amount of parallax between the objects are changed so that the specified object does not overlap with the other objects is proposes as described, for example, in Japanese Unexamined Patent Publication No. 2005-122501.
When displaying an object in a three-dimensionally displayed three-dimensional image, the object is three-dimensionally displayed so as to have a predetermined stereoscopic appearance. If a stereoscopic appearance of a certain portion of a three-dimensionally displayed three-dimensional image is greater than that of the object, however, the object overlaps with the portion and appears to be sunk in the portion. Where the object is formed of only characters or the background of the object is semitransparent or transparent and if the object overlaps with a certain portion of the three-dimensional image, in particular, the three-dimensional image appears very unnatural in which the portion appears to be transparent even though the object appears to be in the back of the portion located in front.
In the method described in Japanese Unexamined Patent Publication No. 2005-065162, distance information is given in advance to both the three-dimensional image and object. If distance information is not given to an image to be three-dimensionally displayed, therefore, it can not be known how the stereoscopic appearance of the object is to be changed. The method described in Japanese Unexamined Patent Publication No. 2005-122501 is a method for preventing objects from overlapping when a certain object included in an image is three-dimensionally displayed and, therefore, the method can not be applied to a case in which the entire image is three-dimensionally displayed.
The present invention has been developed in view of the circumstances described above, and it is an object of the present invention to display, when an object is displayed in a three-dimensionally displayed image, the object without causing uncomfortable feeling arising from the overlapping of the three-dimensional image and the object on top of each other.